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Purpose: The aim of the study was to compare the entrapment efficiency of 5-aminolevulinic acid (ALA) between encapsulated in liposomes and ethosomes.The images of confocal laser scanning microscopy (CLSM) were used to confirm the potency of different vesicles delivering ALA into skin.Method: The preparation of liposomes and ethosomes were performed according to the thin film hydration method, and hydrated with 0.1% ALA in 15% (v/v) aqueous solution or ethanol solution above lipid transition temperature.Vesicle size and zeta potential were measured by laser light-scattering and the entrapment efficiency of ALA in vesicles was determined by ultracentrifuge method.Skin samples were examined for the photosensitizer protoporphyrin Ⅸ (PpⅨ) formed in vivo after the exogenous application of ALA by CLSM.Results: The molar ratio of phosphatidylethanolamine (PE)/cholesterol (CH)/sodium stearate (SS) at 2:1:2.5 in ethosome was represented the best condition to achieve entrapment efficiency of about 66%.The image of confocal laser scanning microscopy (CLSM) revealed that compared to the control group (ALA in H20),increased fluorescence marker of PplX in the skin after treatment by ethosome could clearly be seen with intense signals.Conclusion: For the site treated with ethosomes (PE), there was a broad distribution of PpⅨ that extended from the epidermis and upper dermis.Moreover, the ethosomes (PE) were delivered to a maximum possible depth of 110 μm.